Tails previously included tools to *wipe* files and available disk space. We removed these tools from Tails 6.0 (February 2024), because we think that they are not reliable enough on modern storage devices, such as USB sticks and Solid-State Drives (SSDs).
Operating systems do not actually remove the content of a file when the file is deleted, even after emptying the trash or removing the file from the command line.
Instead, operating systems only mark the space that was used by the deleted file as available for future files, because it is much faster to do. However, the content of the deleted file remains on the device until the operating system reuses the space for another file.
Modern operating systems can store a *journal*, a history of recent changes to the file system, or *snapshots*, an image of the file system at a particular point in time.
Flash memory devices, such as USB sticks and SSDs (Solid-State Drives), have *spare memory cells* that are used to replace broken memory cells over time.Modern hard disks also integrate small flash memories for performance and reliability.
